StarTech PEXUSB3S25 2-Port USB 3.0 PCIe Expansion Card

Overview

The StarTech PEXUSB3S25 is a single-lane PCIe x1 expansion card that adds two USB 3.2 Gen 1 (USB 3.0) Type-A ports to any desktop PC or server with an available PCIe 2.0 slot. If you're running a surveillance workstation, video capture rig, or industrial PC that's exhausted its native USB bandwidth, this card provides a clean, chipset-backed solution without touching your motherboard's existing USB controller. At 5 Gbps per-port theoretical throughput, it's built for the kind of sustained data transfer that USB 2.0 simply can't handle — think high-bitrate capture devices, external storage, or USB-connected IP camera bridges.

The card is built around the Renesas/NEC PD720202 chipset — a well-vetted controller with broad OS and driver support, which matters when you're deploying into an existing Windows or Linux environment and can't afford instability. At 1.8 oz and a footprint of 4.7 in x 3.2 in, it fits standard PCIe x1 slots and ships ready to install.

Key Features

• USB 3.2 Gen 1 at 5 Gbps: Each port delivers up to 5 Gbps — roughly ten times the ceiling of USB 2.0. For high-resolution USB cameras, external NVR backup drives, or industrial scanners, this eliminates the bottleneck that causes dropped frames or stalled transfers on older controllers.
• Renesas/NEC PD720202 Chipset: This is the chipset integrators reach for when driver stability actually matters. Broad OS compatibility means fewer headaches in mixed Windows/Linux server environments, and the chip has a long track record in enterprise deployments.
• 900mA Power Per Port: Each port sources up to 900mA — enough to power most bus-powered USB 3.0 devices without a separate power brick. That's the full USB 3.0 spec-rated current; you won't be scrambling for a powered hub when connecting demanding peripherals.
• PCIe 2.0 x1 Interface: The x1 lane provides sufficient bandwidth headroom for simultaneous operation of both USB ports at full speed. PCIe 2.0 x1 delivers 500 MB/s — well above what two USB 3.0 ports can saturate in real-world use.
• LP4 Auxiliary Power Connector: An included LP4 (Molex) power connector draws supplemental power directly from the PSU, ensuring the ports can deliver the full 900mA per port without relying solely on the PCIe slot's power budget. Skip this connection and you risk current-limited behavior on power-hungry devices.
• USB 2.0 / 1.1 Backward Compatibility: Existing USB 2.0 and 1.1 peripherals connect without adapters or drivers. Useful in environments where legacy devices like card readers, HID inputs, or older capture hardware still need to coexist alongside newer USB 3.0 equipment.
• Operating Temperature 0°C to 50°C: Covers standard server room and office environments. Not rated for outdoor or industrial enclosures — keep this in mind if you're deploying into an edge compute cabinet with limited cooling.
• Compact, Low-Profile Friendly Dimensions: At 4.7 in x 3.2 in x 0.7 in, the card fits easily in standard PCIe x1 slots. Verify your chassis has a free full-height slot — the card is standard height.

Integration and Compatibility

The PEXUSB3S25 installs into any PCIe 2.0 or later x1 (or wider) slot. PCIe is backward and forward compatible at the slot level, so an x4 or x16 slot will physically accept the card if an x1 slot isn't available. The Renesas PD720202 chipset is natively supported on Windows 10/11 and most current Linux distributions, reducing driver provisioning time during deployment. For surveillance integrators pairing this card with USB-connected security peripherals or adding capture ports to a network video recorder workstation, the card installs in minutes with no software beyond the OS driver stack. If you're speccing out a broader PCIe expansion card strategy for a high-density workstation, this card occupies just one x1 lane — leaving other slots free for capture or network cards. See the workstation accessories category for complementary expansion options. For environments adding USB-connected devices alongside IP infrastructure, review the USB hubs and switches lineup for downstream port multiplication.

Frequently Asked Questions

Q: Will the PEXUSB3S25 fit in a PCIe x4 or x16 slot if no x1 slot is available?

A: Yes. PCIe slots are electrically and physically compatible across lane widths — the card will operate correctly in any PCIe x1, x4, x8, or x16 slot. It will still run at x1 speeds, which is sufficient for full USB 3.0 throughput on both ports.

Q: Does the PEXUSB3S25 require the LP4 power connector to function?

A: The card includes an LP4 (Molex) auxiliary power connector that draws supplemental power from your PSU. Connecting it is strongly recommended — it ensures each port can deliver the full 900mA USB 3.0 specification. Without it, power-hungry devices may not operate reliably.

Q: What is the warranty on the PEXUSB3S25?

A: StarTech covers the PEXUSB3S25 with a 2-year manufacturer warranty.

Q: Is the PEXUSB3S25 compatible with USB 2.0 and USB 1.1 devices?

A: Yes. The card is fully backward compatible with USB 2.0 and USB 1.1 devices. Those devices will operate at their native speeds (480 Mbps and 12 Mbps respectively) — not at USB 3.0 speeds.

Q: What chipset does the PEXUSB3S25 use, and why does it matter?

A: The card uses the Renesas/NEC PD720202 chipset. This controller has broad native driver support across Windows and Linux operating systems, which reduces compatibility issues and driver instability compared to less-established chipsets — a meaningful factor in production deployments.

Q: What are the operating temperature limits for the PEXUSB3S25?

A: The card is rated for 0°C to 50°C operating temperature, suitable for standard office and server room environments. Storage is rated from -20°C to 60°C.

Marty Allison

The PEXUSB3S25 is the card I recommend when an integrator asks how to add reliable USB 3.0 ports to an existing surveillance workstation without rebuilding the system. The Renesas/NEC PD720202 chipset is the specific reason — I've seen too many no-name USB expansion cards with obscure controllers cause device dropouts mid-recording, and the PD720202 simply doesn't have that reputation. At 5 Gbps per port and 900mA sourcing capability, both ports are fully spec-compliant, not just labeled as USB 3.0.

Technical Highlights:

• 5 Gbps per port: Full USB 3.2 Gen 1 throughput — adequate for simultaneous high-bitrate USB capture devices or fast external storage on both ports without shared-bus contention issues common in hub-based solutions.
• LP4 auxiliary power: Drawing supplemental current directly from the PSU rather than the PCIe slot means you're not fighting the motherboard's 3.3V/12V PCIe power budget when both ports are loaded at 900mA — a real issue on older workstations with constrained PCIe power rails.
• PCIe 2.0 x1 bus: The x1 lane delivers 500 MB/s of raw bandwidth — roughly 2.5x what two simultaneous USB 3.0 streams can actually consume in practice. No artificial throttling at the bus level.

Deployment Considerations:

• Always connect the LP4 Molex power connector during installation. Skipping it is the most common cause of intermittent device failures on this card class, particularly with bus-powered external drives or high-current USB 3.0 cameras.
• The 0°C to 50°C operating range is a hard limit — this card is not suitable for edge compute enclosures without active cooling if ambient temps approach or exceed 50°C.

For surveillance workstation builds where a VMS server needs additional USB ports for backup storage devices or USB-licensed dongles alongside existing PCIe capture cards, the PEXUSB3S25 is a practical, low-risk addition that won't compete for critical PCIe bandwidth from your capture or network infrastructure.